A couple MB is applied to the drive drum B to maintain a constant speed in the polishing b...

A couple MB is applied to the drive drum B to maintain a constant speed in the polishing belt shown. Knowing that µk = 0.45 between the belt and the 15-kg block being polished and µs = 0.30 between the belt and the drive drum B, determine (a) the couple MB, (b) the minimum tension in the lower portion of the belt if no slipping is to occur between the belt and the drive drum.